Screen



J. BLAND.

SCREEN. APPLICATION HLED JUNE 30, 1920.

1,41 1,834. Patented APT-4,1922.

2 SHEETS-SHEET 1.

IN V EN TOR.

F Z BY j g/g J. BLAND.

SCREEN.

APPLICATION FILED JUNE 30,1 920.

Patented Apr. 4, 1922'.

2 SHEETS-SHEET 2- H. rev/112w INVENTOR. 640g A TTORNEYS.

m E k 4 UNITED STATES JOHN BLAND, OF SAN FRANCISCO, CALIFORNIA.

SCREEN.

Specification of Letters Patent.

Patented Apr. 4, 1922.

Application filed June 30, 1920. Serial No. 392,907.

T 0 all whom it may concern:

Be it known that 1, JOHN BLAND, a citizen of th United States, and a resident of the city and county of San Francisco, State of California, have invented new and useful Improvements in Screens, of which the following is a specification.

My invention has for its object the vibrating of a screen with a substantially vertical amplitude such that material on the screen surface is tossed and thereby frees itself from the surface of the screen, and upon falling back is caused to more ellicicntly pass through the meshes of the screen surface.

Another object is the more efficient screening of the material travelling over the surface of the screen due to the material being out of contact with th screen during a very large part of time and the particles of material are therefore brought into contact with a greater number of meshes in a given period of time.

Another object is a reduction in wear of the surface of the screen due to the great reduction in abrasive action of the material on th screen surface.

Another object is the screening of a given amount of material with less expenditure of power in that no longitudinal movement of the parts of the screen occur, and vertical movement is attained as distinguished from other screening devices wherein the material is shaken laterally on the surface of the screen.

Another object is the employment of less joints for lubrication and reduction in wear and in power employed, and a more efficient and thorough screening of the material.

Other objects will appear from the specification and drawings.

These objects I attain by mounting my screen in a relativelv laterally rigid frame and preferably at an angle of inclination suitable to the descent of the material across the screen surface during operation, and I prefer to make the angle of inclination of the screen adjustable so that it may be readily adapted to different materials.

In one embodiment of my invention as herein set forth I also prefer to support the screen frame at one or more points by a relatively flexible member or plurality of such members, which members are to be rigidly supported at their lower ends and flexed at their central portions with a horizontal amplitude of vibration at which time the fixed end will act as one node and the opposite end, contacting with or connected with the screen or screen frame, will serve as the other node.

The vibration of the central portion of the flexible member I prefer to attain by mounting thereon a bearing on which is carried a suitable shaft and on which shaft is a rotating mass out of balance with respect to its center of rotation. The degree of out-ofbalance of the said mass and the rate of rotation of the shaft will, when properly adjusted, occasion a vibration in a horizontal direction of the vertical flexible mem ber about the two ends as nodes, and the lower end of the said member being fixed, there will result a vertical component of move ment at the opposite end coincident with the horizontal vibration, and it is this vertical component which I employ for the purpose of establishing a corresponding up-anddown movement of the screen, or of the frame and screen.

The screen may be inclined at any suitable angle from the horizontal to facilitate the travel of the material in a downward direction as it is tossed by the rapid up-anddown movement of the screen surface.

By referring to the accompanying drawing my invention will be made clear.

Figure 1 is a perspective view of a screen apparatus employing my invention, and with the pan partly broken away.

Fig. 2 is a end view partly in section of a pair of screens side by side employing case with the apparatus of Fig. 1. 1

my invention and operated from a single motor.

Fig. 3 is a side view of a portion of the screenin apparatus of Fig. 2.

Fig. 4 is a variation in the construction and adaption of the vibrating member to cause vertical reciprocation of the screen.

Fig. 5 is a detail of one of the flexible members of Fig. 1 and indicating the horizontal amplitude and corresponding ver tical displacement transmitted to the screen somewhat magnified.

Fig. 6 indicates a screen in vertical section and showing its vertical movement when the frame is vibrated, as would be the Fig. 7 indicates the vertical amplitude of screen vibration as occasioned by the use of the flexible member and method of operation indicated in Figs. 2, 4 and 9.

Fig. 8 illustrates the bumper device particularly adapted for use with certain classes of material.

Fig. 9 shows a horizontal tie rod restraining the upper end of the flexible member from horizontal movement but permitting its free vertical movement which is directly transmitted to the screen.

Throughout the figures the same numerals refer to identical parts.

The screen is indicated by the numeral 1 formed of well known screen cloth as of either metallic or fabric material and which is indicated as mounted in the frame 2.

Suitable discharging chutes or aprons may be arranged at the downward end of the screen frame as at 3, and the screen frame may with advantage be supported from the uprights 4.- and 5, as by the bearings 6 and cross rod 7 and clamped in any position of adjustment within the range of the quadrant 8 as by the lever nut 9 and I prefer to form on the surfaces of the quadrants. as 8, which are mounted upon the standards 4 and 5, notches with which a washer placed under the nut 9 may be securely clamped with the rod ,7 and the screen frame 2 in its adjusted position; so that the vibration of the apparatus will not loosen the said nuts and throw the apparatus out of adjustment.

At 10 and 11 I have shown bearings or other pivotal connections to the flexible members 12 and 13, the opposite ends of which flexible members as at 14:, 15 respectively are rigidly attached to the frame work 16. These members 12 and 13, in the apparatus illustrated in Fig. 1, form vertical supports for the frame 2'and its contained screen, and mounted substantially at their centers are the bearings 17-18 within which is carried the shaft 19 and on which shaft preferably midway between the members 12-13 is located the pulley, or any suitable rotating element 20.

This rotating element may advantageously be provided with a variable weight as at 21, whereby variation in the position of the weight 21 radially about the shaft center will vary the throw or.amplitude of vibration, thus causing the lateral vibration of the members 12-43, whose ends will vibrate with amplitude 49, substantially as indicated by the dotted lines 2425 of Fig. 5. This will cause a vertical movement of the upper end of the spring members 12- 13 as indicated at 27, which vertical vibration is transmitted to the screen cloth 1, either through the frame 2 as in the construction shown in Fig. 1 or directly to the screen cloth as indicated in Figs. 2, 3 and 4. Where the movement is transmitted to the screen cloth, the construction indicated in Fig. 4 may be employed-in which a head 26 of relatively considerable weightwill be given a vertical component of movement due to the lateral vibration of the members 38 and 39, due to the inertia of the head 26, or as indicated in Fig. 9, the upper end of the spring member 38 will move through a vertical amplitude 27 and be entirely prevented from any lateral vibration by the connecting rod 53 which is secured at its opposite end to the standard 52. Where the construction shown'in Figs. 4 or 9 is employed, it is advisable to reinforce the screen cloth as by the plate 28 below the cloth. I prefer to form the pan 29 in which the screened material is allowed to fall, with an upturned flanged opening as indicated at 31-32 of Fig. 4.

, The pan 29 is left out of the most of the figures for the purpose of more clearly showing the screen, but it is to be understood that it may-be used in connection with the collection of the screened material in any of the well known ways, and the. screened material will travel down the inclined surface ofthe said pan and may be collected from the chute 3 shown diagrammatically at the lower end of the frame 2 Fig. 1.

In Fig. 1 the'motive power for rotating the shaft 19 is obtained from the motor 23 driving the pulley 22 and shaft 19, carrying the rotating element 20, whereas in Fig. 2 the shaft 19 is shown extended on both sides from the motor 33 and is preferably made flexible and fitted with two rotating elements 20-20 which are each carried upon a vertical spring member as 3839 respectively the two spring members are adapted to horizontally vibrate as indicated in Fig. 5 and to cause a vertical reciprocation of the screen 1 as indicated in Figs. 5 a1. 1 9. In the con struction shown in Fig. 2, it will be seen that a plurality of screens may be arranged side b side within a minimum of floor space.

In 7 ig. 6 is shown the path of vertical vibration of the frame and the screen 1 where the said vibration is occasioned through springmembers 12-13 of Fig. 1 and in Fig.

7 is shown the vertical vibration of screen 1 which will take place if the frame 2 is held stationary and the screen only vibrated as by the construction indicated in Figs. 2, 3, 4 and 9.

At times I have found it advantageous to provide a tapping device for the vertically vibrating screen and which is shown in one form in Fig. 8, wherein a bumper head 43 is carried upon a relatively light threaded rod 47 and held in its downward-position by the weight of the parts carried on the rod 40. The screw threaded end 46 acting through the adjustable nut 45 and compression spring 44, limits the extension of the said sprin and is adjustable by the nut 48 on the thread ed rod 47. It will thus be seen that the degree of compression of the spring 44 may be varied at will through the agency of the two nuts 45 and 48. The arm 40 is pivoted at 42, and on its opposite end is provided an adjustable weight 41, such that although the inertia of the parts at the opposite end of the rod is constant, the variation of the position of the weight 41 will permit variations in the pressure of the head 43 caused by the screen 1.

At 50 I have shown an adjusting screw fixed in a bracket 51 such that by varying the position of the said screw the point at which the rod 40 will rest thereon will be varied and so that the head 43 may be adjusted to come into contact with the screen 1 at any position throughout the range of screen Vibration. Due to the inertia of the parts carried on the rod 40, the rapid vibration of the screen 1 will cause a corresponding tapping by the head 43 against the screen surface, the blows of which tapping will be cushioned by the variable spring 44. This device has the function of loosening the ma terial from the surface of the screen due to the constant arresting of the screen during any upward movement, when the particles will be loosened therefrom causing them to rise the necessary height above and then to fall back upon the screen surface.

Where the screen 1 is vibrated directly from the motor mechanism and the frame 2 held in rigid position, the frame construction shown in Fig. 3 is advantageous in which one end of the screen is supported on a frame as at 34 provided with pivots as at 37, so that the inclination of the screen may be varied at will, while the vibration of the screen cloth only is retained at all times throughout the range of said adjustment.

In the screen as set forth in the drawings, there will be two complete cycles of screen vibration to one complete cycle of spring member vibration and therefore the rate of rotation of the driving shaft 19 will be doubled as a vibratory period of the screen.

While I have shown the spring members as 12, 13, 38, 39 as relatively vertical, it will be understood that this applies only at such times as the screen is substantially horizontal and that if the screen be inclined to a material degree a correspondin inclination of said members should also be made, as better results will be attained where the said members are substantially normal to the screen.

Reference is herein made to my co-pending application Serial No. 201,172, filed Nov. 9, 1917, wherein are set forth certain other features of my invention.

I claim:

1. In a screening device, a frame in which is mounted screen means; a plurality of vertical supporting elements of spring material for one end of said frame, means supporting the other end of said frame in pivotal relation and means for vibrating said spring members with a horizontal amplitude whereby vertical reciprocation of the screen means is effected.

2. Apparatus as set forth in claim 1 wherein said means for vibrating comprises a rotary element out of running balance.

3. Apparatus as set forth in claim 1 wherein said means for vibrating comprises a motor constructed and adapted to run out of balance whereby a lateral vibration of said spring elements is effected and also a component vertical reciprocation of the screen coincident therewith.

4. A screen pivota-lly supported at one end and a plurality of spring elements supporting the other end, means connected at substantially the central portion of said elements constructed and adapted to oscillate said elements with a horizontal amplitude whereby the screen is constrained to vibrate with a Vertical amplitude.

5. In screening apparatus, a screen supported in a frame, a member flexible throughout its central part and rigidly fixed at one end and contacting with the screen at the other end, a rotating element out of balance and mounted on a bearing, said bearing COIl. nected to the central part of the flexible member.

6. Apparatus as set forth in claim 5, wherein the end of the flexible member adapted to contact with the screen is constructed of relatively large mass.

7. A plurality of screens mounted parallel with each other and each supported by the upper end of a vertical member of spring material rigidly fixed at its lower end, bearing means on said springs, a common shaft through said bearing means and an element out of running balance on said shaft adapted to rotate whereby the springs are adapted to vibrate on each side of their normal position thereby causing the cycles of movement in the screen to be double that of the said element.

8. In ascreening device, a frame in which is mounted screen means, a plurality of vertical supporting members therefor and of sprin v material, said members fixed against latex-ail movement at their other ends, and means for vibrating said members in unison and on both sides of a central line through their ends.

9. In a screening device, mechanism as set forth in claim 8 wherein said means for vibrating the members comprises an element out of running balance-mounted on the members and adapted to rotate.

10. In a screening device, mechanism as set forth in claim 8 wherein said means for vibrating said members comprises an element out of running balance connected to the members and adapted to rotate.

In testimon whereof, I have hereunto set my hand at an Francisco, California, this 24th day of June, 1920. r

' JOHN BLAND. 

